A mortgage may cover several houses or a number of lots. An operator may have bought a tract of land and subdivided it into lots and placed a mortgage on the whole. His scheme is to sell the lots to individual purchasers. But the mortgage covers each lot; and it is necessary to sell separate lots free of the mortgage. The most convenient manner in which this end may be accomplished is by means of a clause termed "release schedule" inserted in the mortgage. By this schedule a release price is placed on each lot. When this amount is paid, the mortgagee executes an instrument which releases the lot from the mortgage. Of course, even if such a clause were not in the mortgage, the operator could arrange for a release, but it would be a matter for negotiation as to the amount to be paid each time a lot were sold. The schedule in the mortgage saves all this inconvenience and makes it possible for the operator to know in advance just what he must pay to release each lot. It is customary to set the release price on each lot slightly higher than that lot's fair proportion of the loan. This is done so that after each lot is released, the balance better secures the loan. (Appendix form 51.)